Blowing in the wind: Mild hurricane season is no excuse for discounting the risks of climate change

Copyright 2006 Houston Chronicle

Published 6:30 am, Friday, December 1, 2006

Sir, the indignant letter to the editor read, "I continue to be amazed that the Financial Times spends so much time tilting at the windmills of global warming or climate change or whatever we are supposed to call it."

The hurricane season ending next month has been the calmest in years, the writer complained, so it's hard to believe man-made climate change makes much of a difference.

Except perhaps for his civility, that British newspaper reader differs little from some of his Yankee counterparts this week. After all, if one of global warming's effects is worse hurricanes, doesn't tranquil 2006 refute that climate change is a problem?

The answer is no. The question's very premise is flawed. It's true that monster hurricanes are exacerbated by warmer sea surfaces; it's also well-documented that those temperatures have risen in recent decades. Most scientists at this point link this to human carbon emissions.

Yet a host of other variables also swirl into a hurricane's making. That's why the proper response to this quiet season is gratitude, preparation for worse years — and continued study and containment of global warming.

Over the past century, there have been an average 9.6 named Atlantic storms yearly. Since 1995, however, that average has shot up to 14.8 named storms per year. By far the most horrific season occurred in 2005, which included 28 named storms, including the lethal Katrina and Rita. It was the hottest year on record — and, perhaps coincidentally, the most prolific storm season ever documented.

This year, most mainstream climatologists warned, we'd see high levels of hurricane activity, as many as 15-17 storms. But almost to a one, the scientists were wrong. Only nine named storms, it turned out, whipped up off of the Atlantic. Of the five that became hurricanes, none made landfall in North America.

Yet this lull doesn't disprove global warming. In fact, it indicates nothing in particular about climate change. As Chronicle science writer Eric Berger notes, sea temperatures are only one of half a dozen meteorological factors that determine if a storm will be born.

This year, two of those factors were in play simultaneously. Dust moving off the African continent kept some storms from developing, and a strong El Niño — a weather pattern fomented by higher Pacific Ocean temperatures — arose in the second half of the season, swatting down Atlantic storms.

Another confluence like this might happen next year. Or it might not. The only thing certain is that after a year of weather-led tragedy, the United States got lucky in 2006. It's reason for gratitude and relief. It's no reason for arrogant notions that we've got climate change all figured out, or that global warming and the hurricanes it produces pose little risk.